Comparison of sleep variables between chronic widespread musculoskeletal pain, insomnia, periodic leg movements syndrome and control subjects in a clinical sleep medicine practice.

BACKGROUND

Between 50% and 89% of chronic pain patients report unrefreshing sleep. The aim of this retrospective analysis was to compare the sleep of normal subjects with the sleep of a clinical population presenting musculoskeletal chronic widespread pain (CWP), psychophysiological insomnia and restless legs syndrome/periodic limb movements during sleep (RLS/PLMS) in order to identify sleep variables that may explain the poor sleep complaints of CWP patients.

METHODS

Sleep data from 10 normal subjects and 37 patients (mean age 55+/-3 yo), matched for age and sex, were retrieved from our sleep data bank. Sub-analysis controlled for the effects of medication.

RESULTS

In comparison to normal subjects, sleep duration was shorter in CWP patients (-71 min; p<0.01); sleep efficiency was significantly lower in CWP and insomnia patients (-10.1% and -11.1%, respectively; p<0.05). CWP and PLMS patients lost one non-rapid eye movement (REM) to REM sleep cycle (p<0.04). An intermediate level of PLM was observed during the sleep of CWP patients in comparison to normal subjects (8.8/h vs. 2.0/h) and PLMS patients (33/h). Regular use of non-narcotic analgesics did not seem to interfere with sleep variables.

CONCLUSIONS

The sleep of middle-aged patients with CWP is comparable to that of insomnia patients. The moderate level of PLM during sleep suggests that such sensory motor activity needs to be evaluated in patients suffering from chronic pain.